Find the estimated mean of the following frequency distribution.

Class Frequency
0 up to 5 2
5 up to 10 7
10 up to 15 12
15 up to 20 6
20 up to 25 3

Calculate the range, the standard deviation, and the variance.

A sample of the amounts paid for parking on Saturday at the downtown parking garage in Toronto was organized into the following frequency distribution.

Amount Paid Frequency
$0.50 up to $0.75 2
0.75 up to 1.00 7
1.00 up to 1.25 15
1.25 up to 1.50 28
1.50 up to 1.75 14
1.75 up to 2.00 9
2.00 up to 2.25 3
2.25 up to 2.50 2